MILLING TOOL HOLDER WITH THREADED PLUG

PORTE-FRAISE AVEC INSERT FILETE

English Abstract

A milling tool holder axially having a shank with a tapered female
opening, and a tool holder having a tapered mate end that fits into the female
opening. The narrow end of the male end has a bore. A plug having a
threaded opening is inserted in the bore in the tool holder to align the
threaded opening to receive the threaded end of a draw screw. The draw
screw is turned to draw the tool holder and the shank together. When the
draw screw is turned in one direction, the two components are drawn
together, and when turned in the opposite direction the two components may
be separated. A ramming plug in the narrow end of the tool holder expands
the outer surface of the tool holder to wedge the male end in the female
opening.

Claims

Claims
1. A tool holder apparatus, comprising:
an elongated shank intended to be supported for rotation
about a turning axis, said shank having an internal female frustoconical
opening at a first end thereof, and an axial first bore having an inner end
opening to said frustoconical opening;
an elongated tool holder having a first end for supporting
a cutting tool in a cutting position, an external male frustoconical structure
receivable in the frustoconical opening of the shank, and a narrow second end
having an expandable outer surface and axial slots;
the narrow end of the tool holder has an axial bore
therein;
threaded camming structure movably mounted in the tool
holder second bore;
an elongated drawing member received in said first bore
of the shank, the drawing member having an inner threaded end disposed in
said frustoconical opening engageable with the threaded structure in the tool
holder such that as the drawing member is turned about said turning axis in a
first direction, the male end of the tool holder is moved toward a locked
position in the female end of the shank, and as the drawing member is turned
in the opposite direction, the tool holder is axially movable away from the
shank;
the tool holder having a second bore intersecting said first
bore;
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the threaded structure in said second bore comprising;
camming structure disposed in the second bore of the
tool holder, the camming structure having a threaded bore for receiving the
inner threaded end of the drawing member; and
the camming structure being axially movable to a
camming position in the second bore to expand the slotted narrow second
end of the tool holder into engagement with the female opening of the shank;
the drawing member being operative to move the camming structure to
expand the male frustoconicai structure in the female opening to a locked
position.
2. A tool holder apparatus as defined in claim 1, in which the male
second end of the tool holder has a cylindrical expandable outer surface, and
the camming structure is engageable with said second end to expand the
second end in a female cylindrical cavity of the shank to prevent rotational
motion of the tool holder and said shank.
3. A tool holder apparatus as defined in claim 2, in which the
second end of the tool holder has a pair of axial slots permitting expansion
of
said second end.
4. A tool holder apparatus as defined in claim 3, in which the slots
extend to the extreme end of the tool holder second end.
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5. A tool holder apparatus as defined in claim 3, in which said axial
slots have ends spaced from the extreme end of the tool holder second end.
6. A tool holder apparatus as defined in claim 1, in which the
drawing member is a draw screw.
7. A tool holder apparatus as defined in claim 1, in which the
drawing member is a cap screw.
8. A tool holder apparatus as defined in claim 2, in which the tool
holder has a plug-receiving opening between a narrow end of the
frustoconical structure, and a cylindrical end, and the camming structure
includes a plug-receivable in the plug-receiving opening in which a threaded
opening in the plug is aligned in the tool holder's first bore to threadably
engage the drawing member.
9. A tool holder apparatus as defined in claim 3, in which the plug
is disposed in the narrow end of the tool holder adjacent said slots to expand
the expandable outer surface of the tool holder by increasing the distance
between opposite sides of the slots.
10. A tool holder apparatus as defined in claim 1, in which the
camming structure comprises the plug having a pair of keys that extend

beyond the outer surface of the expandable outer surface of the tool holder,
and the female end has a pair of slots for receiving the keys to prevent
rotation of the tool holder with respect to the shank.
11. A tool holder apparatus, comprising:
an elongated shank intended to be supported for rotation
about an axial turning axis, said shank having an internal female
frustoconical
opening at a first end thereof, and an axial first bore having an inner end
opening to said frustoconical opening first end;
an elongated tool holder having a first end for supporting
a cutting tool in a cutting position, an external male frustoconical structure
receivable in the frustoconical opening of the shank the tool holder having a
second end having an expandable outer surface, the tool holder's second end
having an axial second bore therein;
threaded camming structure mounted in the tool holder
second bore;
a differential draw screw received in said shank's first
bore, the differential draw screw having an inner end disposed in the shank
opening and an opposite end engaged with the camming structure such that
as the differential draw screw is turned about said turning axis in a first
direction, the male end of the tool holder is moved toward a locked position
in
the female end of the shank, and as the differential draw screw is turned in
the opposite direction, the tool holder is axially movable away from the
shank;
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said camming structure comprising said second bore
comprising;
a camming member disposed in the second bore of the
tool holder, the camming member having a threaded bore for receiving the
inner end of the differential draw screw; and
the camming structure being axially movable in the
second bore of the tool holder to expand the frustoconical section of the male
structure into engagement with the shank female opening; the differential
draw screw being operative to axially move the camming structure toward the
shank frustoconical opening.
12. A tool holder apparatus as defined in claim 11, including means
for preventing relative rotation between the tool holder and the shank when
the external frustoconical structure of the tool holder is inserted into the
frustoconical opening of the shank.
13. A tool holder apparatus as defined in claim 12, in which the tool
holder has an annular seat around said turning axis, and the differential draw
screw moves the tool holder along said turning axis to a position in which the
annular seat on the tool holder has pressure engagement with an end face of
the shank.
14. A tool holder apparatus as defined in claim 11, wherein the
shank has a pin-receiving opening, and the tool holder has a pin-receiving
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opening, facing the pin-receiving opening the tool holder member, and
including a pin disposed in both of said pin-receiving openings to prevent the
tool holder member from turning about said turning axis with respect to the
shank.
15. A tool holder apparatus as defined in claim 14, in which the pin-
receiving opening in the tool holder member is disposed in a radial direction
and intersects an annular seat of the tool holder, and the pin-receiving
opening in the shank is disposed in a radial direction and intersects an end
face of the shank.
16. A tool holder apparatus as defined in claim 1, in which the tool
holder carries an integrally mounted tool for a cutting motion.
17. A tool holder apparatus as defined in claim 1, in which the
drawing member has an end with a wrench-receiving opening, and the shank
provides access through the shank for a wrench to engage and turn the
drawing screw along said turning axis.
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Description

CA 02487488 2004-11-15
MILLING TOOL HOLDER WITH THREADED PLUG
Cross-Reference to Related Ao~lication
This application is a continuation-in-part of U.S. Patent Application
Serial No. 10/693,418, filed October 27, 2003 for A MILLING TOOL HOLDER
WITH DIFFERENTIAL SCREW.
Background and Summary of the Invention
Tool holders for milling tools commonly employ a male tool-holding
component having a frustoconical end, and a female driven shank having an
opening for receiving the frustoconical end. Various ways are known in the
art for tightly joining the shank to the tool holder.
My prior pending application disclosed a novel way for joining the tool
holder and the shank together to prevent the tool from chattering from tool
movement such as when used in a hydraulic tool system. My earlier invention
prevents tool deflection, and avoids a poorly finished workpiece.
The broad purpose of the present invention is to provide an improved
tool holder combination comprising an elongated tool holder having means at
one end for supporting a milling tool, a. frustoconical or tapered midsection
and a slotted cylindrical end.
The shank has a frustoconical opening for receiving the tapered
section of the tool holder, and an inner cylindrical cavity for receiving the
cylindrical end of the tool holder.
A ramming plug is inserted into the smooth cylindrical bore of the tool
holder transverse to the turning axis of the tool holder. Both the tool holder
and the shank have aligned bores along the turning axis for receiving a draw
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CA 02487488 2004-11-15
screw. The plug has threads aligned with the turning axis of the tool holder.
A draw screw is inserted in the bore of the shank and engages the plug
threads in the tool holder. Turning the screw draws the tapered end of the
tool holder into the frustoconical opening in the shank. The ramming plug
cams the tool to slightly enlarge the diameter of the tool holder in the shank
opening to form a tight fitting connection between the tool holder and the
shank.
Still further objects and advantages of the invention will become readily
apparent to those skilled in the art to which the invention pertains upon
reference to the following detailed description.
Descriation of the Drawings
The description refers to the accompanying drawings in which like
reference characters refer to like parts throughout the several views, and in
which:
FIGURE 1 illustrates a rotatable shank coupled to a tool holder and
showing a tool for turning an internal draw screw for drawing the two
components together; _
FIGURE 2 is a longitudinal sectional view showing the tapered portion
of the tool holder engaging the opening in the shank;
FIGURE 3 is an exploded view showing the tool holder, the draw
screw, and the shank;
FIGURE 4 is a perspective view of the ramming plug;
FIGURE 5 is a view showing the location of the ramming plug in the
tool holder opening;
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FIGURE 6 is a view of a pin that prevents rotation of the tool holder;
FIGURE 7 is an enlarged section view of the ramming plug enlarging
the outside surface of the tool holder;
FIGURE 8 is an enlarged sectional view of another embodiment of the
tool holder;
FIGURE 9 is a fragmentary perspective view of the ramming plug and
the tool holder;
FIGURE 10 is a fragmentary view of another embodiment of the
invention;
FIGURE 11 illustrates a ramming plug for the embodiment of Figure
10; and
FIGURE 12 is an enlarged sectional view as seen along lines 12-12 of
Figure 10.
Description of the Preferred Embodiment
Referring to the drawings, Figure 1 illustrates a preferred tool holder
combination 10 comprising a tool holder 12 joined to a shank 14. A milling
tool 16 is carried, either integrally or by a suitable mounting on the outer
end
of the tool holder. An elongated hexagonal tool 18 is inserted inside the
shank for purposes which will be described. The shank is driven by a rotating
drive means, not shown.
Referring to Figures 2 and 3, tool holder 12 includes a body 20. The
body has an integral frustoconical (tapered) midsection 22 with a large end
terminating in an annular seat 24. The narrow end of midsection 22 has an
integral cylindrical neck 28. Neck 28 also has a pair of aligned axial slots
34
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CA 02487488 2004-11-15
and 36, as best shown in Figure 5, and an internal smooth bore 30. In use
the shank and the tool holder body are rotated about a turning axis 26.
The tool holder has a cylindrical plug-receiving opening 32 formed
along an axis that is transverse to turning axis 26.
Referring to Figure 4, a cylindrical ramming plug 38 is slidably
receivable in plug-receiving opening 32. Plug 38 has an internal right-handed
threaded opening 40 formed in such a manner that when the plug is inserted
in plug-receiving opening 32, threaded opening 40 is aligned with turning axis
26 of the tool holder. Plug 38 has a length that is slightly less than the
diameter of neck 28 so that neither end of the plug extends beyond the profile
of the neck.
Referring to Figure 7, plug 38 has a diameter larger than the width of
slots 34 and 36, and slightly less than the diameter of plug-receiving opening
32.
Plug-receiving opening 32 borders the inner ends of slots 34 and 36,
forming a pair of concave ramming surfaces 41 a and 41 b, which with slots 34
and 36 can slightly expand the diameter of both the neck and the narrow end _
of the tapered midsection. When plug 38 is axially moved toward the slots,
the neck and the narrow end of midsection expand in the areas A and B, and
the distance between opposite sides of the slots can be increased.
Referring to Figure 2, shank 14 has an outer diameter identical to that
of body 20 of tool holder. One end of the shank has a female frustoconical
opening 42 which terminates at its outer end with an annular seat 44 that
mates in face-to-face contact with seat 24.
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CA 02487488 2004-11-15
The narrow end of opening 42 terminates with a short cylindrical bore
36 which receives neck 28. The inner end of bore 46 terminates with end
face 48. Opening 42 is adapted to receive the frustoconical midsection of the
tool holder in a position in which neck 28 enters bore 46 and seat 44 is in
face-to-face contact with seat 24 of the tool holder.
The shank has a left-handed threaded bore 50 which extends along
turning axis 26 and has an inner end opening into bore 46 and an outer end
52 for receiving elongated hexagonal wrench 18.
An elongated draw screw 54 (differential screw) has a threaded end 56
to threadably receivable in threaded opening 40 in ramming plug 38. The
opposite end 58 of the draw screw has an internal hexagonal opening 60 for
mating with the inner end of tool 18 such that tool 18 can be used to turn the
draw screw to urge the tool holder either toward or away from the shank. The
draw screw also has a threaded section 62, receivable in threaded opening
50. Threaded end 56 and threaded section 62 have right and left hand
threads, respectively.
Referring to Figure 6, tool holder 12 has a semi-cylindrical radial
groove 64 in seat 24. The shank has a semi-cylindrical radial groove 66 in
end face 44. A pin 68 is press fitted in a pin-receiving opening 70 formed
when the two radial grooves are rotated to a face-to-face position, and drawn
together. Pin 68 prevents any rotation of the shank with respect to the tool
holder for work requiring a heavy cut. A lighter cut does not require pin 66.
In use, the user aligns the tool holder and the shank in the position
illustrated in Figure 3. He inserts the draw screw through bore 46 until
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CA 02487488 2004-11-15
threaded end 56 engages threaded opening 40 of caroming plug 38. He
threadably engages the outer end of the draw screw with threaded bore 50.
He then inserts tool 18 into the hexagonal bore 72 of the draw screw and
turns the draw screw to pull the tool holder body into shank opening. He
continues this motion until seat 24 of the tool holder and seat 44 of the
shank
are in face-to face contact, and the plug expands neck 28 to tightly engage
the cylindrical wall of bore 46 at B-B. The plug also expands the narrow end
of the tapered midsection of the tool holder to tightly engage the tapered
wall
of the shank at A-A, adjacent slots 34 and 36.
Figure 8 illustrates another embodiment of the invention in which slots
34 and 36 are closed at lip 73. Neck 28 is still expanded by the caroming plug
in the shank opening as in the embodiment of Figure 7.
Figures 9-12 illustrate a modified embodiment 100 of the invention. In
this case, shank 14 has a female frustoconical opening 42 for receiving the
tapered midsection of body 12.
A smooth inner bore 104 in the shank has a pair of longitudinal grooves
106 and 108 on opposite sides of the base. _
Caroming plug 38c is slidably receivable in plug-receiving opening 32
and has a pair of integral keys 38a and 38b receivable, respectively, in
grooves 106 and 108. This arrangement prevents the tool holder from being
turned with respect to the shank. The plug has a threaded bore 40a adapted
to receive the threaded end 56 of the draw screw. The manner in which the
tool holder is joined to the shank is the same as in the embodiment of Figure
3.
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A cap screw (not shown) can be used in place of the differential screw
by making bore 50 smooth with a larger diameter than that of the cap screw
body. The cap of the screw would have a larger diameter than bore 50, and
bear against outer end 74 of the shank (see Figure 1 ).
Having described my invention, I claim:
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Representative Drawing